INTRODUCTION: Auditory hallucinations occur in schizophrenia and also in the general population. However, evidence points to differences in the nature and the mechanisms of clinical and non-clinical hallucinations, challenging the dominant assumption that they represent the same phenomenon. The current study extended this evidence by examining voice identity perception in hallucination-prone individuals. In schizophrenia, deficiencies discriminating between real (external) voices have been linked to basic acoustic cues, but voice discrimination has not yet been investigated in non-clinical hallucinations. METHODS: Using a task identical to that employed in patients, multidimensional scaling of voice dissimilarity judgements was used to examine how healthy individuals differing in hallucination-proneness (30 high and 30 low hallucination-prone individuals) distinguish pairs of unfamiliar voices. The resulting dimensions were interpreted with reference to acoustic measures relevant to voice identity. RESULTS: A two-dimensional "voice space", defined by fundamental frequency (F0) and formant dispersion (Df), was derived for high and low hallucination-prone groups. There were no significant differences in speaker discrimination for high versus low hallucination-prone individuals on the basis of either F0 or Df. CONCLUSIONS: These findings suggest voice identity perception is not impaired in healthy individuals predisposed to hallucinations, adding a further challenge to the continuum model of psychotic symptoms.
INTRODUCTION: Auditory hallucinations occur in schizophrenia and also in the general population. However, evidence points to differences in the nature and the mechanisms of clinical and non-clinical hallucinations, challenging the dominant assumption that they represent the same phenomenon. The current study extended this evidence by examining voice identity perception in hallucination-prone individuals. In schizophrenia, deficiencies discriminating between real (external) voices have been linked to basic acoustic cues, but voice discrimination has not yet been investigated in non-clinical hallucinations. METHODS: Using a task identical to that employed in patients, multidimensional scaling of voice dissimilarity judgements was used to examine how healthy individuals differing in hallucination-proneness (30 high and 30 low hallucination-prone individuals) distinguish pairs of unfamiliar voices. The resulting dimensions were interpreted with reference to acoustic measures relevant to voice identity. RESULTS: A two-dimensional "voice space", defined by fundamental frequency (F0) and formant dispersion (Df), was derived for high and low hallucination-prone groups. There were no significant differences in speaker discrimination for high versus low hallucination-prone individuals on the basis of either F0 or Df. CONCLUSIONS: These findings suggest voice identity perception is not impaired in healthy individuals predisposed to hallucinations, adding a further challenge to the continuum model of psychotic symptoms.
Authors: Kaja Julia Mitrenga; Ben Alderson-Day; Lucy May; Jamie Moffatt; Peter Moseley; Charles Fernyhough Journal: PLoS One Date: 2019-08-12 Impact factor: 3.240
Authors: Louise C Johns; Kristiina Kompus; Melissa Connell; Clara Humpston; Tania M Lincoln; Eleanor Longden; Antonio Preti; Ben Alderson-Day; Johanna C Badcock; Matteo Cella; Charles Fernyhough; Simon McCarthy-Jones; Emmanuelle Peters; Andrea Raballo; James Scott; Sara Siddi; Iris E Sommer; Frank Larøi Journal: Schizophr Bull Date: 2014-07 Impact factor: 9.306